1. Field of the Invention
The present invention generally relates to the field of key operated locks. More particularly, the present invention is directed to locks, and subassemblies therefor, which can be converted between key-retaining and non-key-retaining functions. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Related Art
Key operated locks are broadly classified into two mutually exclusive lock types. Locks of the first type are known as key-retaining locks because in such locks the lock mechanism prevents the key from being removed from the lock while the lock is in an unlocked condition. Locks of the second type are known as non-key-retaining locks because in such locks the lock mechanism permits the key to be removed from the lock while the lock is in the unlocked condition. Most conventional locks only offer one of these lock functions and, hence, are known as single-function locks.
There are practical, functional and security advantages to both types of single-function locks. Since most manufacturers produce single-function locks, lock purchasers normally need to first determine the lock function which meets their particular requirements, and then purchase the single-function lock of the appropriate type. Therefore, locksmiths and other lock suppliers are typically required to stock inventories of both key-retaining and non-key-retaining locks in order to satisfy the needs of all potential lock purchasers.
In order to eliminate the need for locksmiths and other lock suppliers to stock unnecessarily large inventories of both key-retaining locks and nonkey-retaining locks, dual-function locks have been developed. Some exceptionally innovative dual-function padlocks are shown and described in U.S. Pat. No. 5,174,136. Other highly similar dual-function padlocks are shown and described in U.S. Pat. No. 5,363,678. The contents of these two patents are hereby incorporated by reference. Both of these patents represent examples of padlocks which can be readily converted between key-retaining and non-key-retaining functions by the introduction and/or disposal of components between the rotator bolt and the actuator of a lock cylinder. Thus, these locks offer the ability for the purchaser to select the desired lock function at the time of installation or later.
However, none of the dual-function padlocks of the related art can be converted between key-retaining and non-key-retaining functions (i.e., inter1 function lock conversion) without the introduction of and/or the disposal of additional lock components.